What is an SPG?
A Submersible Pressure Gauge (SPG) is a mechanical gauge that connects to your first stage via a high-pressure hose, providing a direct reading of your tank pressure.
Pros of an SPG:
- Reliable & Proven – Decades of use with minimal failure points.
- No Batteries Required – Functions independently of electronics.
- Lower Cost – Simple, inexpensive, and widely available.
- Standardized & Universal – Works with any regulator setup.
Cons of an SPG:
- Requires a Hose – Adds bulk and potential for entanglement.
- Manual Monitoring – No alerts; requires frequent checks.
- Single Data Point – No real-time gas consumption tracking or calculations.
What is an Air-Integrated Dive Computer?
An air-integrated (AI) dive computer connects to your tank either via a wireless transmitter or a hose-connected console, displaying real-time pressure data and calculating estimated remaining dive time based on your gas consumption rate.
Pros of an AI Computer:
- Real-Time Gas Tracking – Calculates remaining bottom time based on gas consumption.
- No Extra Hose (Wireless AI Models) – Streamlined and less clutter.
- Custom Alerts & Warnings – Low gas alarms, turn pressure alerts, and estimated gas time remaining.
- Dive Data Integration – Logs tank pressure and gas usage for post-dive analysis.
Cons of an AI Computer:
- Battery Dependency – Needs power; failures can leave you without gas data.
- Higher Cost – Expensive compared to a basic SPG.
- Compatibility Concerns – Not all transmitters work across brands.
- Potential Signal Loss (Wireless AI) – Transmitters can lose connection in some conditions.
Comparison Table: SPG vs. AI Dive Computer
| Feature | SPG | Air-Integrated Computer |
|---|---|---|
| Reliability | Extremely reliable | Dependent on battery & electronics |
| Cost | Affordable | Expensive |
| Ease of Use | Simple & intuitive | More complex setup & pairing |
| Data Tracking | No gas consumption tracking | Real-time SAC rate & gas time remaining |
| Alerts & Warnings | None | Low gas alarms, turn pressure alerts |
| Hose-Free Option | No | Wireless AI models available |
| Failure Risk | Low (mechanical) | Higher (electronics, batteries, signal loss) |
What’s Best for You?
Choose an SPG if:
- You prioritize simplicity and reliability.
- You want a lower-cost, low-maintenance solution.
- You don’t want to worry about batteries or electronic failures.
- You strictly follow DIR (Doing It Right) or GUE-style diving configurations.
Choose an AI Computer if:
- You want real-time gas tracking and alerts.
- You prefer a clutter-free setup with a wireless transmitter.
- You dive with variable gas consumption rates and want data analysis.
- You like having integrated dive logs for post-dive review.
The Best of Both Worlds?
Some divers use both an air-integrated dive computer for convenience and an SPG as a backup in case of electronics failure. This is a popular choice among divers who want the benefits of AI while maintaining a fail-safe. This is usually what I do unless I'm trying to maximum weight savings, then I remove the SPG.